1. Field of the Invention
The invention is directed to a valve for controlling the flow of fluid; and, more particularly, the invention is directed to an in-line valve having a simplified valve stack construction.
2. Related Art
Contemporary in-line valves comprise a fitting with a valve seat seal, which is mounted in a fluid or water supply line. Typically, a portion of the supply line is removed and the fitting replaces the removed portion. The fitting is usually threaded on or welded to the supply line.
The valve seat includes a rotatable shaft extending from the interior to the exterior of the fitting. The exterior end of the shaft mounts a handle or similar structure for grasping and rotating the shaft. The interior end of the shaft is mounted to a disk or washer. As the handle is rotated, the valve seat is moved into or out of compressive contact with a seal to close or open the valve depending on the direction of handle rotation.
One disadvantage of the valve seat seal is that it requires multiple turns of the shaft to fully open or fully close the valve seat. It can also take a substantial amount of force to rotate the shaft and to compress the valve seat a sufficient amount to obtain an adequate seal. As the valve seat wears, especially from over-tightening, greater compressive force is usually needed to obtain a complete seal. The multiple rotations of the handle and the excessive force needed to rotate the handle and seal the valve is considered an inconvenience by many users.
An alternative to the valve seat seal is a disk stack, which generally takes the form of a fixed disk and a rotating disk, each having corresponding openings that are aligned in one rotational position to permit water flow and un-aligned in another rotational position o prevent water flow. Examples of such in-line valves are show in U.S. Pat. Nos. 3,426,797, issued Oct. 20, 1965 and 5,088,689, issued Feb. 18, 1992.
The disk stacks are advantageous in that the control of water flow running through the disks is dependent on the rotational position of the disks, instead of the axial compressive force of the seat seal valve. The ceraminc disks are are disadvantageous in that they are difficult to manufacture and are subject to breakage.